Dolphin Smash is a mixed-signal, multi-language simulator for IC or PCB designs. It uses SPICE syntax for analog descriptions, Verilog-HDL and VHDL for digital, Verilog-A/AMS, VHDL-AMS and ABCD (a combination of SPICE and C) for analog behavioral, and C for DSP algorithms.

Electric is a complete EDA system that can handle
many forms of circuit design, including Schematic
Capture (digital and analog), Custom IC layout,
Logic Simulation, Electro-mechanical hybrid
layout, Programmable logic (FPGAs) and much more.

Gnu Circuit Analysis Package is a general purpose
circuit simulator. It performs nonlinear DC and
transient analysis, fourier analysis, and AC analysis.
Spice compatible models for the MOSFET (level 1-
7) and diode are included. This project is not based
on Berkeley Spice, but some of the models have
been derived from the Berleley models. It was
formerly known as 'Al's Circuit Simulator'.

Qfsm is a graphical editor for easily drawing finite state machines, written in C++ using Qt. Transitions can have either binary or ASCII conditions. Machines can be simulated and integrity checks applied, enabling verification of proper design and operation.

Slam is a mature IC Layout editor with the ability
to edit very large designs (such as stream files
larger than 10GB). Novel features include
threading for redraw, support for displaying on
multiple X servers simultaneously, and a Tcl
interface to the database for user extensibility.
The system is a library based system with
multi-user support. Programmable structures
(P-Cells) are available in Tcl. The editor
includes gds input and output.

TkGate is an event-driven digital circuit simulator with a TCL/Tk-based graphical editor. It supports a wide range of primitive circuit elements and user-defined modules for hierarchical design. The distribution comes with a number of tutorial and example circuits which can be loaded through the "Help" menu, and the example circuits include a simple CPU, programmed to run the Animals game. TkGate has multi-lingual support for English, Japanese, French, German, Spanish, Welsh, and Catalan.